Isolation tanks or sensory deprivation tanks are lightless and sound proof chambers in which a person floats near the surface of very dense salt water maintained at about 34 degrees Celsius which is the normal human body temperature. The density of the water is kept high with the addition of copious amounts of Epsom salt to the water so that the person in the tank can float near the water surface with face out of the water. An isolation tank is thus configured to completely isolate a person from external stimuli such as ambient light, background noise and hot or cold sensations generally present in the atmosphere which are experienced by the person's skin. Sensory-deprivation studies of short-term and well-moderated experiences result in relaxation of the subjects similar to hypnosis or meditation.